Association between adherence to the Nordic diet and frailty in older adults: A systematic review of observational studies

Abstract

Background: The Nordic or Baltic Sea diet is a healthy plant-based dietary pattern composed of foods originating from Nordic countries, closely related to the Mediterranean diet. Adherence to the Mediterranean diet has been found to be associated with a reduced risk of frailty. Although adherence to the Nordic diet has been associated with health benefits, little is known about its association with frailty.

Objectives: To investigate the evidence from observational studies regarding the association between the Nordic/Baltic Sea diet and frailty among older adults.

Design: Systematic review.

Methods: Three databases (Medline/Ovid, Embase/Ovid, and Scopus) were systematically searched in February 2023 for observational studies examining the association between adherence to the Nordic diet and frailty among adults ≥60 years. The two authors independently assessed the full text of the papers for eligibility of studies and risk of bias.

Results: Three studies (the results of which were reported across 6 papers) met the inclusion criteria, among which one study (2 papers) included only women. Greater adherence to the Nordic diet was associated with a reduced risk of frailty measured by modified Fried criteria in women (one study). Moreover, greater adherence to the Nordic diet was associated with improved muscle (handgrip/leg) strength (one study) and physical performance (two studies), but these differences were seen only in women, with no significant results in men in two studies. Greater adherence to the Nordic diet was also associated with a lower risk of mobility limitations and improved ability to carry out self-care tasks (one study) and a borderline non-significant difference in Activities of Daily Living (one study). A meta-analysis was not performed due to heterogenous outcomes. Although all studies were of good quality, the results should be carefully interpreted due to methodological limitations.

Conclusions: Adherence to the Nordic diet could be promising in reducing frailty risk, but more robust studies with equal gender representation and frailty-specific outcomes are needed.

Keywords: Alternative diet; Dietary pattern; Functioning; Gait speed; Healthy diet; Muscle strength.